KALAMATA, Greece May 26, 2012— -- William Winram makes it sound so easy. "You're going to hold your breath, pull yourself down a line under the sea," says the champion deep diver from Canada.

Tribe of ‘fish people’ boast extra-big spleens for deep sea diving By . Jon Lockett, The Sun. Published April 20, 2018. Updated April 20, 2018, 7:10 p.m. ET. AFP/Getty Images ...

In the very early days of free-diving, physiologists were pretty convinced that people couldn’t go beyond about 30 or 40 metres. They’d drawn their graphs as scientists and they’d worked out ...